Why does sandy soil have a higher bulk density than a clay soil?
Sandy soils are comprised of larger (and fewer) solid particles than clayey soils. These particles are irregularly shaped and so “fit” together in a way that creates spaces between particles. More particles = more space, especially when you consider the difference in particle sizes we are talking about here. Sand > 50 micrometers. Clay < 2 micrometers (USDA classification system). More space results in lower bulk density.
